In recent years, in a field of display units that perform image display, there has been developed and commercialized a display unit (an organic EL display unit) that uses, as a light emitting device, a current-driven optical device in which light emission luminance varies in accordance with a value of a current passing therethrough, for example, an organic EL (Electro Luminescence) device. Unlike a device such as a liquid crystal device, the organic EL device is a self-emitting device, and it is not necessary to provide a light source (a backlight) therefor. Therefore, the organic EL display unit has characteristics such as high visibility of an image, low power consumption, and high response speed of device, compared to the liquid crystal display unit in which the light source is necessary.
As a driving scheme of the organic EL display unit, there are a simple (passive) matrix scheme and an active matrix scheme as with the liquid crystal display unit. The former has a simple structure; however, has an issue such as difficulty in achieving large and high-definition display unit. Therefore, currently, the latter active matrix scheme has been actively developed (for example, Patent Literature 1, etc.). In this scheme, a current that passes through an organic EL device arranged for each pixel is controlled by a transistor in a pixel circuit provided for each organic EL device.